| abstract |
The present invention provides a solution which is for improving the stability of a precursor compound for a radioactive fluorine-labeled compound, and in which a compound represented by formula (2) or a salt thereof is stored in a state of being dissolved in an organic solvent (in the formula, X1 represents a hydrogen atom or a halogen atom, X2 represents a fluorine atom or a nitrile group, R1 represents a substituted or unsubstituted alkylsulfonyloxy group, or a substituted or unsubstituted arylsulfonyloxy group). |